regular fsck runs are too disturbing - and current approach does not work very well in detecting defects!

[Phillip Susi]

Jan Claeys wrote:
> The main reason (IMO) why "defrag" is not useful (anymore) is that for
> ages there hasn't been any (guaranteed) correlation between hardware
> order and software order of sectors on a disk.  Defragmenting disks
> might actually fragment them more on a fysical level, and thus cause
> slow-downs.  And in some cases (fysically) fragmented sectors might be
> faster to read/write than non-fragmented ones (I used a custom,
> partially self-written, diskette formatting program to do exactly that
> under MS-DOS!).  So, any defrag program would require help from the hard
> disk's firmware to be really efficient (and AFAIK no firmware supports
> this).

No, the only time the logical sectors become physically out of order are 
when defect remapping has taken place.  Sequential reads of sectors in 
order are still the fastest way to access the disk, so access to files 
which are not fragmented is faster than files which are.